Scientists Work to Tie Uranium Cubes to Nazis

At the close of World War II, some 664 "Heisenberg cubes" belonging to the Nazis were dug up from a field near physicist Werner Heisenberg's secret subterranean lab and brought to the US. Kurt Diebner was at the same time also running a lab focused on trying to make an atomic bomb; hundreds more uranium cubes from his lab vanished. Today, the whereabouts of only about 12 Heisenberg cubes are known, but Live Science reports that number could soon increase. That's because scientists have devised some ways to try to establish whether other cubes belong to that original bunch, and they're starting with a cube that wound its way in a mysterious fashion to researchers at the Pacific Northwest National Laboratory (PNNL) in Washington state. More:

• As Gizmodo explains, the provenance of the cubes is murky, thanks to slipshod distribution: After the war, they were "disseminated into universities and private ownership, through formal and informal channels."
• In 2019, NPR recounted the story of one such potential cube, which physicist Timothy Koeth of the University of Maryland was given in a parking lot; it was in a bag, wrapped in paper towels. In addition to its own, PNNL has access to Koeth's cube, as well as a few others. "We don’t know for a fact that the cubes are from the German program, so first we want to establish that," says project lead Jon Schwantes. "Then we want to compare the different cubes to see if we can classify them according to the particular research group that created them."
• They'll use radiochronometry to date the cubes and "analyze rare-earth element impurities" within them as well as their coatings, as a press release explains. The result of the latter analyses may reveal which lab they hailed from.
• As for the Nazis' failed attempt, the press release explains: "Hundreds of the cubes were hung on cables submerged in 'heavy' water, in which deuterium replaces lighter hydrogen. The scientists hoped radioactive decay of the uranium in the assemblies would unleash a self-sustaining nuclear chain reaction—but the design failed."
• Breathe easy: NPR noted in 2019 that because the cubes are made of natural uranium, they're neither very radioactive nor valuable.

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